The present invention relates to notification of incomplete calls and, more particularly, but not exclusively to a method and apparatus for supporting notification to a called party regarding calls made to him which for one reason or another he did not answer.
At present there are two main groups of incomplete call notification systems. The first and most widespread of these, currently applying to both mobile and wireline systems, is voice mail. In the wireline version, a call which remains unanswered after a timeout is transferred to a mailbox. A message is read out to the caller who leaves a message after a tone. Additionally a call may be transferred to a mailbox when the called telephone is busy. In the wireless version the called telephone may be in one of three unavailable states, busy, not available on the network and available but not answering. In all three states it is desirable to divert a caller to the mailbox.
The disadvantage of the mailbox is that voice messages require relatively large amounts of storage. Thus a mailbox, or voicemail, service is often provided as an extra for which the user pays.
A second solution is caller ID. In the wireline environment a caller ID device extracts the caller line identification (CLI) information from an incoming call, possibly together with date and time information and displays the information on a screen. The device may be able to display a certain number of previous callers, and may be incorporated into a telephone or may be included in a stand-alone device. The caller ID devices do not discriminate between completed and non-completed calls. In the wireless environment, if a call reaches a mobile telephone then the caller ID details are generally available to the user, again irrespective of whether the call was completed. If however the telephone is disconnected at the time of the call, then the voice mail facility is the only way that the user can know about the call.
Caller ID has been extended in the wireless environment to situations in which the mobile telephone is not connected at the time of the call. In such a case a network switch detects details of the incomplete call and sends those details as an SMS message to the mobile telephone. The message is then received the next time the user connects to the network and the user is notified of the uncompleted call.
The disadvantage of caller ID in the wireline environment is that it is dependent upon suitable equipment at the user end. The mobile solution is of course not applicable to the wireline environment since fixed telephones are not generally able to handle SMS messages.
Nevertheless it is desirable to notify a user whenever possible of non-completed calls so that the user has the opportunity to return the call. From the point of view of the service provider, every non-completed call is a source of lost revenue and every opportunity to inform a user of the incomplete call is an opportunity to recover that revenue.
There is thus a need for, and it would be highly advantageous to have, a way of notifying a user of incomplete calls which is effective for the wireline environment, which is not associated with a voicemail facility or like resource-intensive features, and preferably which can also provide details of calls which are aborted prior to any time out period.